Research On The Control Theory Of Grid-Connected Inverter In Micro-Grid

In2009, our country puts forward building a "strong and smart grid-project". According to the plan, the future of our country in the energy structure will have major change,(pv) power, wind power and fuel cells and various kinds of distributed power generation will greatly increase. But if the large number of distributed generation directly connect to the power grid will have cause an impact and have a high cost, so micro-grid technology times produced. Micro-grid in the integration of distributed power generation unit has a big advantage, it weakened the impact of the distributed power connect to power grid and reduce the cost. It through the integration of distributed generation units and the relationship between the distributed network, directly to make the distributed Power generation units, power network send end user stronger in a local area. It can optimize the structure, and configuration easily.This paper first introduced the development of domestic and foreign micro-grid, and generalizes all of the country’s main system structure. As the type of distributed generation and micro characteristics of a grid, inverters based on power electronics technology will be widely used in micro-grid. So, how to solve the grid coordinated inverter control problem is the stable operation of the power grid able to key, is also the focus of research in this paper.This paper domain contrast research L, LC, LCL filtering properties of the filter in frequency and selected LCL filter as this paper main research object. Then introduces several common method of the grid-connected inverter, finally selected SPWM control method as this paper research method. This paper summed up the common inverter topology Based on the Micro-grid choose three-phase bridge topology. Then establish instantaneous voltage current2-ring control of the grid inverter model, And according to the characteristics of the micro-grid transmission line is divided into rated power control and voltage/frequency control, based on the design theory development and drooping sagging controller. Using MATLAB/SIMULINK to simulate single and multi inverters parallel operation.